Paige is exactly right. It took you years to come to acceptance. Give her at least a few months.
And regarding the back and forth...I think it's completely normal given the gigantic revelations of the past week. Anger, denial, acceptance, etc, etc. And besides, do you feel exactly the same way about everything all the time? Of course not. And her willingness to apologize is the same as admitting that she behaved badly. That's a step in the right direction for sure.
I'd say that sex may not necessarily be a preoccupation, but a roadblock. And it's a good sign if that's the biggest one. For my wife, she's fine with the idea of being seen socially as a lesbian, and she's even mostly fine with me transitioning. At this point it's the idea of being with a woman sexually that's throwing her off. It's really one of her only objections. I'm really hoping she can get over it or at least adjust to the changes.
Perhaps most importantly, do your best to give her a reason to stick with you through this. Be a good wife. Worst case scenario she still wants to leave and at least you'll have done as much as possible to make it an amicable split over irreconcilable differences. But your efforts could also make her want to stick with you through this.
